import logging
from typing import Optional

import requests
from flask import current_app, redirect, request
from flask_restx import Resource
from sqlalchemy import select
from sqlalchemy.orm import Session
from werkzeug.exceptions import Unauthorized

from configs import dify_config
from constants.languages import languages
from events.tenant_event import tenant_was_created
from extensions.ext_database import db
from libs.datetime_utils import naive_utc_now
from libs.helper import extract_remote_ip
from libs.oauth import GitHubOAuth, GoogleOAuth, OaOAuth, OAuthUserInfo
from models import Account
from models.account import AccountStatus
from services.account_service import AccountService, RegisterService, TenantService
from services.errors.account import AccountNotFoundError, AccountRegisterError
from services.errors.workspace import WorkSpaceNotAllowedCreateError, WorkSpaceNotFoundError
from services.feature_service import FeatureService

from .. import api

logger = logging.getLogger(__name__)


def get_oauth_providers():
    with current_app.app_context():
        if not dify_config.GITHUB_CLIENT_ID or not dify_config.GITHUB_CLIENT_SECRET:
            github_oauth = None
        else:
            github_oauth = GitHubOAuth(
                client_id=dify_config.GITHUB_CLIENT_ID,
                client_secret=dify_config.GITHUB_CLIENT_SECRET,
                redirect_uri=dify_config.CONSOLE_API_URL + "/console/api/oauth/authorize/github",
            )
        if not dify_config.GOOGLE_CLIENT_ID or not dify_config.GOOGLE_CLIENT_SECRET:
            google_oauth = None
        else:
            google_oauth = GoogleOAuth(
                client_id=dify_config.GOOGLE_CLIENT_ID,
                client_secret=dify_config.GOOGLE_CLIENT_SECRET,
                redirect_uri=dify_config.CONSOLE_API_URL + "/console/api/oauth/authorize/google",
            )

        oauth2 = OaOAuth(client_id='', client_secret='', redirect_uri='') # Extend: oauth2

        OAUTH_PROVIDERS = {"github": github_oauth, "google": google_oauth, "oauth2": oauth2}
        return OAUTH_PROVIDERS


class OAuthLogin(Resource):
    def get(self, provider: str):
        invite_token = request.args.get("invite_token") or None
        OAUTH_PROVIDERS = get_oauth_providers()
        with current_app.app_context():
            oauth_provider = OAUTH_PROVIDERS.get(provider)
        if not oauth_provider:
            return {"error": "Invalid provider"}, 400

        auth_url = oauth_provider.get_authorization_url(invite_token=invite_token)
        return redirect(auth_url)


class OAuthCallback(Resource):
    def get(self, provider: str):
        OAUTH_PROVIDERS = get_oauth_providers()
        with current_app.app_context():
            oauth_provider = OAUTH_PROVIDERS.get(provider)
        if not oauth_provider:
            return {"error": "Invalid provider"}, 400

        # extend: 兼容casdoor
        id_token = None
        code = request.args.get("code")
        state = request.args.get("state")
        # Fallback: some providers may return tokens directly in query (implicit/hybrid flow)
        token_from_query: Optional[str] = None
        if not code:
            token_from_query = request.args.get("access_token")
            if token_from_query:
                logger.warning(
                    "oauth.callback_no_code_but_token",
                    extra={
                        "provider": provider,
                        "full_url": request.url,
                        "note": "Using access_token from query as fallback. Prefer Authorization Code flow.",
                    },
                )
            else:
                return {"error": "Missing authorization code"}, 400
        invite_token = None
        if state:
            invite_token = state

        try:
            if token_from_query is not None:
                token = token_from_query
            else:
                # Extend: Start 兼容casdoor
                response_json = oauth_provider.get_access_token(code)
                token = response_json.get("access_token")
                if not token:
                    return {"error": f"Error in OAuth: {response_json}"}, 502
                id_token = response_json.get("id_token")
                # Extend: Stop 兼容casdoor
            # 检查token是否有效
            if not token or token.strip() == "":
                logger.error("OAuth2 access token is empty for provider %s", provider)
                return {"error": "OAuth2 access token is empty or invalid"}, 400

            user_info = oauth_provider.get_user_info(token)
        except requests.RequestException as e:
            error_text = e.response.text if e.response else str(e)
            error_status = e.response.status_code if e.response else "Unknown"
            logger.exception("An error occurred during the OAuth process with %s (Status: %s): %s",
                           provider, error_status, error_text)

            # 提供更具体的错误信息
            if error_status == 401:
                return {"error": f"OAuth2 authentication failed (401 Unauthorized): {error_text}"}, 400
            elif error_status == 400:
                return {"error": f"OAuth2 bad request (400): {error_text}"}, 400
            else:
                return {"error": f"OAuth process failed (Status: {error_status}): {error_text}"}, 400
        except ValueError as e:
            logger.exception("OAuth2 configuration error for provider %s: %s", provider, str(e))
            return {"error": f"OAuth2 configuration error: {str(e)}"}, 400

        if invite_token and RegisterService.is_valid_invite_token(invite_token):
            invitation = RegisterService._get_invitation_by_token(token=invite_token)
            if invitation:
                invitation_email = invitation.get("email", None)
                if invitation_email != user_info.email:
                    return redirect(f"{dify_config.CONSOLE_WEB_URL}/signin?message=Invalid invitation token.")

            return redirect(f"{dify_config.CONSOLE_WEB_URL}/signin/invite-settings?invite_token={invite_token}")

        try:
            account = _generate_account(provider, user_info)
        except AccountNotFoundError:
            return redirect(f"{dify_config.CONSOLE_WEB_URL}/signin?message=Account not found.")
        except (WorkSpaceNotFoundError, WorkSpaceNotAllowedCreateError):
            return redirect(
                f"{dify_config.CONSOLE_WEB_URL}/signin"
                "?message=Workspace not found, please contact system admin to invite you to join in a workspace."
            )
        except AccountRegisterError as e:
            return redirect(f"{dify_config.CONSOLE_WEB_URL}/signin?message={e.description}")

        # Check account status
        if account.status == AccountStatus.BANNED.value:
            return redirect(f"{dify_config.CONSOLE_WEB_URL}/signin?message=Account is banned.")

        if account.status == AccountStatus.PENDING.value:
            account.status = AccountStatus.ACTIVE.value
            account.initialized_at = naive_utc_now()
            db.session.commit()

        try:
            TenantService.create_owner_tenant_if_not_exist(account)
        except Unauthorized:
            return redirect(f"{dify_config.CONSOLE_WEB_URL}/signin?message=Workspace not found.")
        except WorkSpaceNotAllowedCreateError:
            return redirect(
                f"{dify_config.CONSOLE_WEB_URL}/signin"
                "?message=Workspace not found, please contact system admin to invite you to join in a workspace."
            )

        token_pair = AccountService.login(
            account=account,
            ip_address=extract_remote_ip(request),
        )
        # extend: 兼容casdoor
        return redirect(
            f"{dify_config.CONSOLE_WEB_URL}?access_token={token_pair.access_token}"
            f"&refresh_token={token_pair.refresh_token}&id_token={id_token}"
        )


def _get_account_by_openid_or_email(provider: str, user_info: OAuthUserInfo) -> Optional[Account]:
    account: Optional[Account] = Account.get_by_openid(provider, user_info.id)

    if not account:
        with Session(db.engine) as session:
            account = session.execute(select(Account).filter_by(email=user_info.email)).scalar_one_or_none()

    return account


def _generate_account(provider: str, user_info: OAuthUserInfo):
    # Get account by openid or email.
    account = _get_account_by_openid_or_email(provider, user_info)

    if account:
        tenants = TenantService.get_join_tenants(account)
        if not tenants:
            if not FeatureService.get_system_features().is_allow_create_workspace:
                raise WorkSpaceNotAllowedCreateError()
            else:
                new_tenant = TenantService.create_tenant(f"{account.name}'s Workspace")
                TenantService.create_tenant_member(new_tenant, account, role="owner")
                account.current_tenant = new_tenant
                tenant_was_created.send(new_tenant)

    if not account:
        if not FeatureService.get_system_features().is_allow_register:
            raise AccountNotFoundError()
        account_name = user_info.name or "Dify"
        account = RegisterService.register(
            email=user_info.email, name=account_name, password=None, open_id=user_info.id, provider=provider
        )

        # Set interface language
        preferred_lang = request.accept_languages.best_match(languages)
        if preferred_lang and preferred_lang in languages:
            interface_language = preferred_lang
        else:
            interface_language = languages[0]
        account.interface_language = interface_language
        db.session.commit()

    # Link account
    AccountService.link_account_integrate(provider, user_info.id, account)

    return account


api.add_resource(OAuthLogin, "/oauth/login/<provider>")
api.add_resource(OAuthCallback, "/oauth/authorize/<provider>")
